Effects of frequent, small doses of calcium carbonate on water quality and phytoplankton in channel catfish ponds

摘要

Finely pulverized calcium carbonate was added to 0.04-ha ponds at Auburn, Alabama, three times per week between 1 July and 11 October 1997 at 8 kg/ha for each application . Channel catfish Ictalurus punctatus were stocked and fed, and ponds were aerated 6 h each night following usual commercial practices. Calcium carbonate treatment reduced phytoplankton activity apparently through precipitation of soluble reactive phosphorus as calcium phosphate. There was less net oxygen production by phytoplankton in the ponds treated with calcium carbonate than in control ponds, but calcium carbonate treatment did not reduce cyanobacteria abundance. Small, frequent doses of calcium carbonate did not appear useful as a pond treatment for controlling phytoplankton and stabilizing water quality under the conditions existing in this study.